EAS tags have been used for many years as a means of deterring retail shoplifting in clothing stores, electronic stores, and a myriad of other retail establishments. Generally speaking, an EAS system will consist of a durable and reliable, yet small, sensor tag which is affixed to the article to be detected in such a way that it cannot be easily removed by a customer in the store. Usually, the system depends on the feature that the attachment mechanism is constructed such that it can only be removed by the use of a specialized tool which is only in possession of the store personnel at the checkout register or exit port for the establishment. In the event that an EAS tag is not removed from a protected article prior to exiting the store, an alarm or other signal is activated.
In order for an EAS system to be reliable, the tag must be effective in that a shoplifter will be unable to remove it within the store. In some systems, the tag is encapsulated with an ink cartridge which will open and permanently destroy the protected item and make a considerable mess in the process. In other systems, the tag is attached with an attaching element that will cause destruction of the article if it is pulled or ripped from the article. In addition, the tag attaching element must be rigid enough to withstand efforts to crack it open within the store. In short, the EAS tag must be called upon to perform reliably amid challenges by the most clever and aggressive of shoplifters.
Although an assortment of attaching elements are available in the prior art, one of the more common and more successful attaching elements consists of a tack which is used to physically pin the protected article to the EAS tag base. The tack has a shaft and cap. The shaft inserts through the protected article into a tension mechanism in the tag body, and the cap retains the tag on the protected article. The tag base is usually constructed of a hard and durable plastic and is generally in the neighborhood of three inches long. A variation on the tack within the prior art is a lanyard ending in a pin, or shaft. One end of the lanyard is fixed to the tag body while the other end terminates in a pin shaft. The lanyard wraps around a portion of the object to be protected and the pin shaft inserts into a retention mechanism in the tag body.
The tag serves as a housing for an electronic signal generation means secured within the housing, which is designed to be immune to tampering. The security system is further characterized by one or more system receiver/transmitters which generate an interrogation zone in the general vicinity of the exit door to the retail establishment. The interrogation zone is usually defined by the installation of one or more transmitters adjacent to the exit doorway. When an EAS tag is moved into or through the surveillance zone, an electronic transmitter within the EAS tag's electronic signal generation means will cause a signal to be generated which will be received by a system receiver to indicate that an unauthorized presence of a tagged article has been detected within the interrogation zone. Accordingly, alarms may sound or personnel may otherwise be alerted to the event such that the shoplifting can be thwarted at the exit port of the retail establishment.
In some embodiments of EAS tags, the electronic signal transmitter may be a passive EAS element. A passive EAS element is energized by the interrogation field when in the field and generates a signal with this energy. One type of passive EAS element is a ferrite core with a conductive coil wrapped around it. When in the presence of the interrogation field, the core and coil have energy stored in them by the field. When the field is terminated, the energy from the core and coil dissipates, and the element generates a signal in the process. The broader EAS system detects this signal and therefore detects the tag in the interrogation field. Other passive EAS elements include magneto-restrictive elements.
In some embodiments of EAS tags, the electronic signal transmitter may be one element of several electronic elements in an active electronics package with an onboard power supply such as a battery. The electronic signal transmitter may be a radio frequency transmitter operating in conjunction with a microprocessor and the electronics may receive signals as well as transmitting them. Other forms of wireless communication, such as optical communication, may also be enabled with the appropriate electronics in the tag. Optical wireless communication may comprise infrared communication ports that receive infrared signals and light emitting diodes that transmit infrared signals.
Most of the tack-based or lanyard-based EAS tags are constructed such that the tags which are removed at the checkout register may be re-attached to other merchandise for re-use. In general, the shaft attaching element of the EAS tag may only be removed through the operation of a specialized detaching mechanism by store personnel. A common detaching mechanism is a magnetic detacher. These detachers use a magnetic force to release the pin or tack shaft from a retention mechanism. There are several mechanisms within the prior art that can be released by the application of a sufficiently strong magnet.